The invention concerns an ink ribbon for a printer, typewriter or the like, more particularly but not exclusively a transfer ribbon for a thermal transfer printer.
An ink ribbon for a printer or the like is often provided with a sensing or control strip, referred to hereinafter as the control strip, which is adapted to produce an optical effect. The control strip may be disposed at the leading end or the trailing end or at both ends of the ribbon. The optically operative control strip, in conjunction with a suitable sensor arrangement in the printer, provides that, when the end of the ink ribbon is reached, the ink ribbon stops and further operation of the printer is disabled. Hitherto, various kinds of control strips have been used, more particularly in dependence on the nature of the layer of ink on the ink ribbon. If a transparent control strip is used, light can suddenly pass through the control strip at the end of the ink ribbon when the control strip reaches the sensor arrangement of the printer, and as a result the procedure for switching off the printer is triggered. It is however also possible to use a light-impervious control strip so that, when the control strip passes into the region of the corresponding sensor arrangement, less light is allowed to pass through the control strip, in comparison with the ink ribbon. That reduction in the degree of transmission of light then represents the signal for the printer to be switched off. Now, hitherto the situation was such that different control strips have been used in dependence on the different types of printers for which the ink ribbons are intended, more specifically, either control strips which have a higher degree of light-transmissivity or transparency relative to the ink ribbon, or control strips whose light-transmissivity or transparency is less than that of the ink ribbon. That involves an increased level of expenditure, both in regard to the manufacturer of the ink ribbons and also in regard to the dealers trading with such articles. Moreover, if a user inadvertently employs an ink ribbon with an unsuitable control strip, which is possible in view of the fact that the ink ribbons or the cartridges thereof are otherwise of the same configuration, that can even give rise to serious damage to the printer.
JP-A-3(1991)-75185 discloses a thermal transfer ribbon in which the control strips are longitudinally divided. Control strip portions having a multiplicity of alternately transparent and opaque regions are provided at one end above the line of division of the control strip and at the other end below that line of division. That makes it possible to distinguish between the leading end and the trailing end of the ink ribbon. However, such a ribbon can also only be used with certain types of printer.